My lmp was on 1/07/14.I had a protected sex using condom on 22/07/14. I have not yet received my periods. Do I have any chance of getting pregnant. I am taking premolut and to start my periods.

There is always a chance for pregnancy when having sex. Taking Premolut is meant to change the uterine lining from hospitable state to the shedding state. I don't know what would have if there was an already implanted embryo. Are you on any other contraceptives?

I would consult your doctor before you do anything. Wait a few more days, end of the week, and take a pregnancy test to see if you're pregnant. Don't discontinue taking the pills but realize that it can cause birth defects. I am not sure if that is later in the term or in the early, early term. Regardless it sounds like Premolut isn't a contraceptive.